+ _enter("");
+
+ if (vnode->lock_state == AFS_VNODE_LOCK_GRANTED ||
+ vnode->lock_state == AFS_VNODE_LOCK_EXTENDING) {
+ cancel_delayed_work(&vnode->lock_work);
+
+ vnode->lock_state = AFS_VNODE_LOCK_NEED_UNLOCK;
+ afs_lock_may_be_available(vnode);
+ }
+}
+
+/*
+ * Check that our view of the file metadata is up to date and check to see
+ * whether we think that we have a locking permit.
+ */
+static int afs_do_setlk_check(struct afs_vnode *vnode, struct key *key,
+ afs_lock_type_t type, bool can_sleep)
+{
+ afs_access_t access;
+ int ret;
+
+ /* Make sure we've got a callback on this file and that our view of the
+ * data version is up to date.
+ */
+ ret = afs_validate(vnode, key);
+ if (ret < 0)
+ return ret;
+
+ /* Check the permission set to see if we're actually going to be
+ * allowed to get a lock on this file.
+ */
+ ret = afs_check_permit(vnode, key, &access);
+ if (ret < 0)
+ return ret;
+
+ /* At a rough estimation, you need LOCK, WRITE or INSERT perm to
+ * read-lock a file and WRITE or INSERT perm to write-lock a file.
+ *
+ * We can't rely on the server to do this for us since if we want to
+ * share a read lock that we already have, we won't go the server.
+ */
+ if (type == AFS_LOCK_READ) {
+ if (!(access & (AFS_ACE_INSERT | AFS_ACE_WRITE | AFS_ACE_LOCK)))
+ return -EACCES;
+ if (vnode->status.lock_count == -1 && !can_sleep)
+ return -EAGAIN; /* Write locked */
+ } else {
+ if (!(access & (AFS_ACE_INSERT | AFS_ACE_WRITE)))
+ return -EACCES;
+ if (vnode->status.lock_count != 0 && !can_sleep)
+ return -EAGAIN; /* Locked */
+ }
+
+ return 0;
+}
+
+/*
+ * Remove the front runner from the pending queue.
+ * - The caller must hold vnode->lock.
+ */
+static void afs_dequeue_lock(struct afs_vnode *vnode, struct file_lock *fl)
+{
+ struct file_lock *next;
+
+ _enter("");
+
+ /* ->lock_type, ->lock_key and ->lock_state only belong to this
+ * file_lock if we're at the front of the pending queue or if we have
+ * the lock granted or if the lock_state is NEED_UNLOCK or UNLOCKING.
+ */
+ if (vnode->granted_locks.next == &fl->fl_u.afs.link &&
+ vnode->granted_locks.prev == &fl->fl_u.afs.link) {
+ list_del_init(&fl->fl_u.afs.link);
+ afs_defer_unlock(vnode);
+ return;
+ }
+
+ if (!list_empty(&vnode->granted_locks) ||
+ vnode->pending_locks.next != &fl->fl_u.afs.link) {
+ list_del_init(&fl->fl_u.afs.link);
+ return;
+ }
+
+ list_del_init(&fl->fl_u.afs.link);
+ key_put(vnode->lock_key);
+ vnode->lock_key = NULL;
+ vnode->lock_state = AFS_VNODE_LOCK_NONE;
+
+ if (list_empty(&vnode->pending_locks))
+ return;
+
+ /* The new front of the queue now owns the state variables. */
+ next = list_entry(vnode->pending_locks.next,
+ struct file_lock, fl_u.afs.link);
+ vnode->lock_key = afs_file_key(next->fl_file);
+ vnode->lock_type = (next->fl_type == F_RDLCK) ? AFS_LOCK_READ : AFS_LOCK_WRITE;
+ vnode->lock_state = AFS_VNODE_LOCK_WAITING_FOR_CB;